1. Technical Field
This invention relates in general to resuscitators and, more particularly, to a resuscitation system for use with various patient sizes.
2. Description of the Related Art
Emergency medical personnel, and others, are often called upon to ventilate patients who have stopped breathing. Loss of spontaneous breathing can occur in many situations, particularly in drowning situations, asthma, allergic reations, cardiopulmonary arrest and respiratory arrest. Once spontaneous breathing has stopped, it is imperative to restore breathing as soon as possible, but until that can be accomplished, emergency personnel must breathe for the patient.
In many situations, mouth-to-mouth resuscitation is used to restore normal breathing in a patient or is used to artificially breathe for a patient. Mouth-to-mouth resuscitation has several drawbacks, including contact with the body fluids of a stranger. Therefore, manual resuscitators have been developed. A manual resuscitator is used with a face mask or endotracheal tube and an inflatable ventilation bag. The ventilation bag is typically filled with air from the surrounding atmosphere or with oxygen (or oxygen-rich air) from a supply tank. With the face mask covering the patient's mouth and nose, the operator squeezes the ventilation bag, forcing the air/oxygen in the ventilation bag into the patient's lungs. As the ventilation bag is released, the patient exhales, and the ventilation bag is refilled with air/oxygen. The operator can continue this cycle until the patient begins spontaneous breathing without external aids, or until such time that the patient can be aided by an automatic resuscitator.
On each pump cycle, as the air/oxygen is pumped into the patient's lungs, it is important that the correct amount of air/oxygen be applied. For an adult, the ventilation bag generally expels between 1500 and 2000 cc of air/oxygen. For a child, only 600-750 cc are expelled and for pediatrics, only 200 cc are expelled. If an operator squeezed the full amount of an adult ventilation bag into a child patient, the child's lungs would likely burst.
One solution is to include a safety release valve on the mask which will open if the pressure inside the mask exceeds a certain level. The safety release valve, while beneficial in some cases, may fail to open in time to prevent serious injury, and is therefore not entirely reliable.
The use of a single resuscitation device to accommodate the lung sizes of different age classes has been the subject of several patents. In U.S. Pat. No. 3,046,978 to Lea, a ventilation bag with markings for different age groups is provided, whereby the volume of air delivered to the patient varies depending upon where the ventilation bag is squeezed. U.S. Pat. No. 5,520,173 to Kuhn offers a similar solution hereby the ventilation bag has gripping sections with varying cross-sections for each age group. In U.S. Pat. No. 5,301,667 to McGrail et al, a pressure limiting valve can be set at various positions to control the pressure of the ventilation gas applied to the patient. Similarly, U.S. Pat. No. 4,821,713 provides a rotatable cap with various vent openings which can be positioned to accommodate various age groups. U.S. Pat. No. 5,645,056 describes an air bag having a volume which is constricted by a belt which can be tightened according to the patient's weight.
While these aforementioned devices address the need for different gas volume levels for different patients, they all suffer from a significant flaw. Under the stress of an emergency, all of these devices could be misused, resulting in catastrophic damage to a patient's lungs. When time is of the essence, less experienced persons, such as lifeguards or family members, and even experienced emergency medical personal, can miss a required setting or squeeze at the wrong place on the ventilation bag.
Accordingly, most emergency medical crews carry separate devices for each age class in the emergency vehicles. Because of space considerations, however, only the device size needed is packed in the emergency kit taken to the scene. The emergency medical crews pack the device based on information from a dispatcher. This can often lead to problems, as inaccurate communications often occur between the person who called for help and the dispatcher or between the dispatcher and the emergency medical personnel. For example, the dispatcher may communicate the patient is a eighteen year old, where, in fact, the patient is a eight year old. Similarly, the dispatcher may report that the patient is a sixteen year old, where, in fact, the patient is a sixteen month old. In these cases, the emergency medical personnel must return to the vehicle to get the properly sized equipment, wasting precious time.
Therefore, a need has arisen for a method and apparatus for effectively resuscitating a patient of arbitrary size.